The relative atomic mass of copper is 63.55. Calculate the percentage of $_{{\text{29}}}^{{\text{63}}}{\text{Cu}}$ in the naturally occurring element.

State the full electronic configuration of a copper atom.

Explain why most copper(II) compounds are coloured, whereas most copper(I) compounds are not.

(i)     Using data from Table 14 of the Data Booklet, calculate the cell potential for this reaction.

(ii)     Use this result to predict, with a reason, whether this reaction will be spontaneous.

$63x + 65(100 - x) = 63.55 \times 100$;

$(x = ){\text{ }}72.50(\% )$;

Award [2] for correct final answer.

${\text{1}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{p}}^{\text{6}}}{\text{3}}{{\text{s}}^{\text{2}}}{\text{3}}{{\text{p}}^{\text{6}}}{\text{3}}{{\text{d}}^{{\text{10}}}}{\text{4}}{{\text{s}}^{\text{1}}}/{\text{1}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{p}}^{\text{6}}}{\text{3}}{{\text{s}}^{\text{2}}}{\text{3}}{{\text{p}}^{\text{6}}}{\text{4}}{{\text{s}}^{\text{1}}}{\text{3}}{{\text{d}}^{{\text{10}}}}$;

Do not accept upper case letters or numbers as subscripts.

colour is due to movement of electrons (between d orbitals) / OWTTE;

copper(I) has a full d sub-shell(, hence electrons cannot move) / copper(II) has an incomplete d sub-shell(, hence electrons can move) / OWTTE;

(i)     $\left( {E_{{\text{cell}}}^\Theta  = 0.15 - 0.52 = } \right) - 0.37{\text{ (V)}}$

choosing correct ${E_{{\text{cell}}}^\Theta }$ values;

combining in correct way;

Award [2] for correct final answer.

Award [1] for –0.18 (0.34 instead of 0.15) and –0.19 (0.34 instead of 0.52).

(ii)     not spontaneous because ${E^\Theta }$ negative / OWTTE;

This question in general was well answered, with an encouraging number of students being able to both calculate the proportions of the two isotopes of copper and state its atypical electron configuration. Responses to part (c) often centred around the splitting of d-orbitals rather than their completeness and a disturbing number of answers implied, or stated, that transition metals emit, rather than absorb light. In the final part, as might have been predicted, a significant number of students used the electrode potential for ${\text{C}}{{\text{u}}^{2 + }}{\text{/Cu (}} + {\text{0.34 V)}}$, rather than those required, but a number of them managed to gain some credit by combining this with the other potential in a valid manner and correctly predicting the spontaneity that it would imply.

This question in general was well answered, with an encouraging number of students being able to both calculate the proportions of the two isotopes of copper and state its atypical electron configuration. Responses to part (c) often centred around the splitting of d-orbitals rather than their completeness and a disturbing number of answers implied, or stated, that transition metals emit, rather than absorb light. In the final part, as might have been predicted, a significant number of students used the electrode potential for ${\text{C}}{{\text{u}}^{2 + }}{\text{/Cu (}} + {\text{0.34 V)}}$, rather than those required, but a number of them managed to gain some credit by combining this with the other potential in a valid manner and correctly predicting the spontaneity that it would imply.

This question in general was well answered, with an encouraging number of students being able to both calculate the proportions of the two isotopes of copper and state its atypical electron configuration. Responses to part (c) often centred around the splitting of d-orbitals rather than their completeness and a disturbing number of answers implied, or stated, that transition metals emit, rather than absorb light. In the final part, as might have been predicted, a significant number of students used the electrode potential for ${\text{C}}{{\text{u}}^{2 + }}{\text{/Cu (}} + {\text{0.34 V)}}$, rather than those required, but a number of them managed to gain some credit by combining this with the other potential in a valid manner and correctly predicting the spontaneity that it would imply.

This question in general was well answered, with an encouraging number of students being able to both calculate the proportions of the two isotopes of copper and state its atypical electron configuration. Responses to part (c) often centred around the splitting of d-orbitals rather than their completeness and a disturbing number of answers implied, or stated, that transition metals emit, rather than absorb light. In the final part, as might have been predicted, a significant number of students used the electrode potential for ${\text{C}}{{\text{u}}^{2 + }}{\text{/Cu (}} + {\text{0.34 V)}}$, rather than those required, but a number of them managed to gain some credit by combining this with the other potential in a valid manner and correctly predicting the spontaneity that it would imply.